DiscussionAlt Acc and Main Acc - how do bans work?

I found a thread on here from 2014 about people saying that if you get banned on an Alt, your main can also be banned. Is that real? Will your main be also banned if you get banned for hacking on an Alt account? I turned off family sharing on both accounts so they aren't linked to my knowledge at least. I'm obviously not going to start the cheat when I play on my main.

To simplify it: what other precautions should I take to not get banned, and is this true? Can you be banned on your main if you're VACed on your main?

Assuming they use the same IP, Valve may get smart and ban both. Mostly not, though, since siblings and all exist.
To not get banned, I would treat it as if the other account does not exist to you: no trades, no steam messages, nothing.
Treat it as if you don't even know what it is.